A traffic jam makes everyone arrive late for a different private reason.

A shared delay is only shared on the surface. Everyone in the queue is stationary in the same place, and one is missing a hospital appointment, one is late for a child at a gate, one is losing an hour of a holiday, and one does not mind at all. The traffic is identical; the cost is completely different in every car. Whatever is happening to a group, it is happening to individuals with separate stakes.

When you are stuck alongside strangers, hold the possibility that this is much worse for somebody nearby. Letting a car in, or waving somebody through, costs almost nothing from where you sit.